In the light of the higher stresses being imposed on the bridges and viaducts by today's train loads and speeds, British Railways has pursued a three-year inspection of all such facilities. To monitor any potential deterioration a three-boom jib with telescopic reach and an inspection bucket, remotely controlled by the operator, permits the necessary close-up survey of any structure on which track is laid. The road chassis of a commercial unit was replaced with a modified well-type flat car.